Grain grinder

ABSTRACT

A grain grinder having a rotor stone rotated by a power source and a stationary stator stone. The rotor stone has novel tapered and spirally configurated grooves therein for evenly distributing grain about the rotor stone so that grinding takes place uniformly around the periphery of the stone. Novel external adjustment structure is provided to vary the clearance between the stator stone and the rotor stone so that various grains may be ground to a desired texture by selecting a position on an indicator or display device which visually displays the clearance set between the rotor stone and the stator stone.

United States Patent Barger Feb. 1, 1972 [54] GRAIN GRINDER 1,033,878 7/1912 Craig ..241/256 [72] Inventor: Dales R. Barge R0. Box 221 Downey, 1,435,130 11/1922 Hogan ..24l/296 Idaho 83234 Primary Examiner-Granville Y. Custer, Jr. [22] Filed: May 14, 1970 Attorney-Lynn G. Foster [211 Appl. No.: 37,071 [57] ABSTRACT A grain grinder having a rotor stone rotated by a power source 65;: and a stationary stator stone. The rotor stone has novel tapered and spirally configurated grooves therein for evenly [58] Field of Search ..24l/245, 248, 255, 256, 296 distributing grain abou the rotor Stone so hat grinding takes place uniformly around the periphery of the stone. Novel ex- [56} References cued ternal adjustment structure is provided to vary the clearance UNITED STATES PATENTS between the stator stone and the rotor stone so that various grams may be ground to a desired texture by selecting a POSI- 1,705,996 3/1929 Pope ..241/256 X tion on an indicator or display device which visuany displays 2 Z in the clearance set between the rotor stone and the stator stonev 585,536 6/1897 Rose ..24l/255 9 Claims, 5 Drawing Figures PATENTED H58 1 I972 MEET 18? a INVENTOR. DELOS R. BARGER ATTORNEY assaan PATENTED FEB 1 972 SHEET 2 OF 2 INVENTOR.

DELOS R. BARGER ATTORNEY GRAIN GRINDER BACKGROUND 1. Field of the Invention The present invention relates generally to grain grinders and, more particularly, to a grain grinder forming a grain product of selected uniform texture.

2. The Prior Art It is desirable, when grinding various size grains, to be able to regulate or vary the clearance between the rotating and stationary grinding stones so that desired texture of the resulting flour or granular product can be obtained. Conventional grinders provide adjustment between the rotor and stator grinding stones only by complicated adjustment internal of the grinder. Normally, some disassembly of the grinder is required before the adjustment structure is accessible.

Moreover, conventional grain grinders frequently experience failures of the bearings supporting the rotating stone because of concentrated, nonuniform grinding action occurring primarily at one radial grinding location between the stones. This results in uneven forces imposed upon the stone and causes bearing failure. Various devices such as blowers or fans have been used in an effort to distribute the grain more evenly around the stone so that grinding takes place more uniformly. Furthermore, when grinding occurs primarily in one location, the stationary stone at that location has a tendency to wear more rapidly and requires replacement sooner than had the grinding taken place uniformly over the grinding surface of the stones.

BRIEF SUMMARY AND OBJECTS OF THE INVENTION The presently preferred grain grinder embodiment ofthe invention provides a novel grinding stone which evenly distributes granular material between the grinding surfaces of the stator and rotor grinding stones. Improved adjustment structure is also provided exterior of the grinder for selectively varying the separation between the stator and rotor stones to accommodate facile selectivity of the texture of the ground grain product.

It is, therefore, a primary object of the present invention to provide an improved grain grinder.

It is another valuable object of the present invention to provide novel readily accessible structure for adjusting the separation between grinding stones.

One still further object of the present invention is to provide a novel grinder which provides a uniformly textured ground product.

These and other objects and features of the present invention will become more fully apparent from the following description and appended claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top perspective view of a presently preferred embodiment ofthe invention;

FIG. 2 is a cross-sectional view taken along lines 2-2 of FIG. 1;

FIG. 2a is a fragmentary perspective illustrating the manner in which a manual crank may be coupled to the shaft of the motor;

FIG. 3 is a perspective view of a presently preferred rotor stone embodiment of the invention; and

FIG. 4 is an enlarged fragmentary cross-sectional elevation of the grinding stone assembly and adjustment mechanism of FIG. 2.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT A presently preferred embodiment of a grain grinder is illustrated in FIG. I. The grain grinder 10 comprises a housing 12 having a front face 14 (FIG. 2) and a rear face l6joined by cylindrical center portion 18. Above the housing 12 is a hopper 20 which is suitable for holding grain prior to grinding. The hopper 20 has four sides 22 which connect to a bottom 24 tapering to an opening 26 formed in the bottom. The hopper 20 rests on and is supported by the housing 12. A stand 28 is secured to the lower portion of the housing 12, stand 28 having legs 30 and cross-supports 32. The stand 28 supports the housing 12 on a suitable surface such as a table (not shown).

The interior of the cylindrical portion 18 of the housing 12, best shown in FIG. 2, contains a motor 34 which may be any suitable conventional electric motor. The motor has a front driving shaft 36 which connects to a rotor grinding wheel 48 as will be hereinafter more fully described. A rear shaft 38, integral with shaft 36, has a male end with a flat extension 40 adapted to receive a mating female socket portion 41 of a hand crank 43 (FIG. 2a). The socket portion 41 of the crank 43 is inserted through an opening 42 in the rear face 16 of housing 12. The right hand end of the socket portion 41 comprises a small aperture 45 through which a capscrew 47 may loosely pass. When the crank 43 is appropriately coupled to the flat extension 40, as when the motor 34 is temporarily of permanently incapacitated, the capscrew 47 may be fitted through the aperture 45 and threadedly secured in a threaded blind bore 49 of the flat extension 40. In this way, the crank 43 is secured to the motor shaft 38 for manual rotation thereof to accommodate grinding of grain.

The motor 34 is secured to mounting plate 124 (FIG. 4) attached by suitable fasteners to the housing 18. Plate 124 has an opening 128 through which shaft 36 rotatably passes. Grain deflectors 126 are radially spaced around the periphery of the plate 124 and project away from the mounting plate 124. The grain deflectors 126 form an annular passageway 150 which is in open communication with discharge conduit 152.

As heretofore mentioned, the shaft 36 of the motor 34 connects to a rotor stone 48. A fan or turbine plate 138 having turbine blades 140 secured to the periphery thereof is nonrotatably mounted upon the shaft 36 between the mounting plate 124 and the rotor stone 48. The blades 140 project away from the turbine plate 138 so as to be radially spaced around the peripheral edge of the rotor stone 48. The blades 140, when rotated, tend to draw milled grain from between the stones 48 and 50 into an annular passageway and, thereafter, to the collector or bag hanger 152 located at the bottom of housing 12, as will be subsequently more fully described.

The center portion of the turbine plate 148 comprises a hub 142 (FIG. 4) which telescopes over shaft 36. The hub 142 nonrotatably receives a sleeve 143 at the hollow interior thereof, the sleeve 143 being held against rotation in respect to the hub by a key 107 which fits within aligned grooves 145 and 149 of the hub and sleeve, respectively. The sleeve is restrained against axial displacement relative to the hub by a set screw 153 which forcibly engages sleeve 143 at location 151, the setscrew 153 being threadedly carried in radial bore 155 of the turbine plate 148. The motor shaft 36 telescopes within the hollow bore 147 of the sleeve 143 and is nonrotatably held in that relation by a key 157 snugly interposed in aligned grooves 159 and 163 of the shaft 36 and sleeve 143, respectively. The left end of the sleeve 143 is threaded at the bore 147 and receives a capscrew 146. In this way the bore 147 is closed to prevent entry of grain, etc.

The rotor stone 48 has a through bore 154 into which the hub 142 is integrally secured. The stone 48 has a front grinding surface 156 and a rear surface 158. The rear surface 158 is bonded or otherwise suitably secured to the plate 138. The grinding of the grain occurs principally near the outer periphery of surface 156 as will be hereinafter more fully described. It should also be observed that the turbine blades 140 are greater in axial length than the thickness of the rotor stone 48 so as to project beyond the grinding surface 156 (see FIG. 3). Also, rotor stone 48 is maintained upon the hub 142 by a nut secured to a threaded portion 176 of the hub 142. The nut 170 has tangentially projecting wings 172 (best shown in FIG. 3) which aid in distributing the grain over the grinding surface 156.

Grooves 160 have been provided in the grinding surface 156 of rotor stone 148. As shown in FIG. 3, the grooves 160 are spirally configurated and taper from a relatively deep center portion 162 to become flush with grinding surface 156 at 164. The deep portion 162 may have a greater width than shallow portion 164 or, if desired, the width of grooves 160 may be uniform. For example, one presently preferred embodiment has been found to adequately distribute grain over the entire grinding surface when grooves 160 have a maximum depth of one-eighth inch, a uniform width of one-fourth inch and traverse and arcuate path 2% inches in length.

When grain is supplied to the center portion of the rotor stone 48, grain enters the grooves 160 and because of centrifugal force due to the rotation of stone 48, the grain is dispensed at 164 generally uniformly over the periphery of the stone 48. Thus, grinding can occur uniformly over the grinding surface of the stone 48 rather than only in one radial location.

The grinding surface 156 of rotor stone 48 is closely spaced from a stator stone 50. The grinding of the grain or like takes place between the grinding surface 56 of stator stone 50 and the grinding surface 156 of the rotor stone 48.

Stator stone 50, in the illustrated embodiment, is generally disc-shaped and has an annular central opening 52 through which grain can flow. A sloped composite face 54 is juxtaposed to the stone 50 to form an outwardly converging grain passageway therebetweenv The opening 52 of the stone 50 merges with a first surface 161 having a relatively steep taper. The surface 161 merges into a more moderately tapered surface 163 which in turn merges into a surface 56 which is normal to the axis of the opening 52. By reason of the composite face 54, grain is fed through the space between the stones 48 and 50 at a confined rate to insure proper grinding. The stone 50 has a back surface 58 which may be secured such as by bonding to a stator plate generally designated 60.

The stator plate 60, in the illustrated embodiment, has mounting 62 and a bottom 64 which supports the weight of the stator stone and stator plate on the housing 12. The stator plate 60 also has a chute portion 65 which forms a passageway 66 through which the grain may flow from hopper opening 26 to the opening 52 in the stator stone. The chute portion 65 and the bottom 64 are joined to a front wall 68 which has a boss 70 directed inwardly toward the mounting 62. The boss has a threaded bore 72. The stator stone and stator plate are axially displaceable in the housing 18, but prevented from rotating relative to the housing 18 by a male coupling 120 (FIG. 4) which couples with mating female coupling (not shown) in projection 122 ofmotor-mounting plate 124.

As can be observed in H0. 1, a screw 80 having a diametrally enlarged portion 82 engages the threaded bore 72 in the stator plate 60. The screw 80 further has a diametrally reduced portion 84 which fits within a vertically oriented U- shaped slot 86 formed in the front plate 14. The screw 80 has another diametrally enlarged portion 88. The screw 80 can be rotated in the U-shaped slot and is held in position by shoulders 90 and 92 of the diametrally enlarged portions 82 and 88, respectively. Rotation of the screw 80 causes the diametrally enlarged threaded portion 82 to rotate in the threaded bore 72 and thus will axially displace the stator plate 60 and stator stone 50 to and fro relative to the rotor stone 48 to selectively vary the clearance between the stator and rotor stones. Thus, it is possible to adjust the clearance between the stator stone and rotor stone in order to regulate or control the texture of the ground grain product after grinding.

As shown in FIGS. 1 and 4, an indicator plate 94 having graduations 95 is secured to the face 14 such as with screws 98. Screws 98 are disposed through elongated, arcuate slots 96 in the plate, which slots allow selective adjustment of the plate 98 to calibrate the graduations 95 and actual spacing of the rotor and stator stones. The indicator plate 94 has an opening 100 through which the diametrally enlarged portion 88 of screw 80 passes when plate 94 is removed. A washer 102 is secured by a locknut 104 having radially projecting wings 106 to the screw 80. The locknut 104 provides a way of holding or retaining the adjustment between the rotor stone 48 and the stator stone 50 by locking or fixing the axial position of screw 80.

To facilitate adjustment of the clearance between the stones, an adjustment handle-pointer 108 is secured to a square leading and 110 of screw 80. The handle-pointer 108 has a square aperture 112 adapted to receive the square leading end 110 of the screw 80. The handle-pointer 108 is further secured to the screw with threaded screw 114. Since the handle-pointed is exterior of the housing 18. it is convenient and easy to rotate the handle-pointer to vary the clearance between the rotor and stator stones. Further, the position of the handle-pointer 108 relative to the graduations on the indicator plate 94 displays the clearance set between the rotor and stator stones 48 and 50, respectively.

In the operation of the grinder 10, grain is introduced into the hopper 20 and flows through the opening 26 in the hopper 20 through the passageway 66 and into the aperture 52 of the stator stone. The grain is guided by the wings 172 of the nut 170 into the grooves 160 and, thereafter, centrifugal force of the moving rotor stone will cause the grain in the grooves 160 to be uniformly distributed over the grinding surface 156 of the rotor stone 48.

When the grain has been properly ground into flour, meal or the like, turbine blades complement the centrifugal force developed by rotor stone 48 to draw the ground grain product into the annular passageway 150. The ground product thereafter collects at the bottom of annular passageway and falls through the conduit 152.

Preferably, conduit 152 is disposed within the opening ofa bag or jar used to collect the grain product.

When the texture of the grain product is to be varied, the handleindicator 108 may be manually rotated to any one of a plurality of radial positions indicated by graduations 95 so that the spacing between grinding stones 48 and 50 is changed.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the range and equivalency of the claims are therefore to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a grain grinder comprising a housing and a stator stone, the improvement comprising a rotor stone having a grinding portion and a feeding portion, said feeding portion being in open communication with a supply of grain and having at least one groove of substantially uniform width therein adapted to assist the transportation of said grain from said feeding portion to said grinding portion, said groove beginning at a point adjacent but spaced from the central opening of the stone and spiraling toward the periphery of the stone, and power means for rotating the rotor stone relative to the stator stones.

2. A grain grinder as defined in claim 1 wherein said stator stone comprises:

a central opening through which grain is supplied to the feeding portion of the rotor stone,

a first surface extending about the periphery of said opening and tapering outwardly from said opening at a relatively steep angle,

a second surface extending about the periphery of said first surface and tapering outwardly from said first surface at a relatively moderate angle, and

a third surface extending about the periphery of said second surface normal to the axis of said opening.

3. In a grain grinder as defined in claim 2, wherein said rotor stone further comprises blower means comprising a pluralityof turbine blades radially spaced around the periphery of the rotor stone to assist in transporting grain product after it has been ground.

4. In a grain grinder having a housing, a stator stone and a rotor stone, the improvement comprising an axially displaceable mounting plate upon which the stator stone is mounted, the weight of the plate being carried by the housing and externally adjustable means comprising a single screw rotatably secured to the housing and threadedly engaging the stator stone mounting plate so as to axially displace the mounting plate and thereby vary the clearance between the stator stone and the rotor stone when the screw means is rotated.

5. A grain grinder as defined in claim 4 wherein said screw means comprise a handle-pointer manually displaceable to rotate the screw means and an indicator plate having indicia thereon to visually indicate the clearance between said stones.

6. In a grain grinder as defined in claim 5 wherein said indicating plate is adjustable relative to the stator stone to accommodate calibration between the separation of the rotor and stator stones and the indicia.

7. In a grain grinder as defined in claim 4 wherein said adjustable means further comprises locking means to maintain a predetermined clearance between the stator and rotor stones.

8. In a grain grinder as defined in claim 4 wherein said mounting plate comprises a chute portion adapted to feed grain from a grain source to the clearance between the rotor and stator stones.

9. A grain grinder comprising a housing, a rotor stone mounted for rotation in a vertical plane, means for rotating the stone, a stator stone spaced from and in general alignment with the rotor stone, means coupled to the stator stone for delivering grain through an opening in the stator stone to a grinding location between the stator and rotor stones and externally adjustable means for varying the space between the rotor and stator stones, said adjustable means comprising horizontally oriented screw means rotatable to axially displace the stator stone relative to the rotor stone, said rotor stone having at least one groove in the grinding face thereof to generally uniformly distribute grain to the periphery of the rotor stone for grinding, said stator stone having a tapered surface extending outwardly about the periphery of said opening and a second surface extending about the periphery of said tapered surface normal to the axis of said opening in facing relation with the grooved surface of said rotor stone. 

1. In a grain grinder comprising a housing and a stator stone, the improvement comprising a rotor stone having a grinding portion and a feeDing portion, said feeding portion being in open communication with a supply of grain and having at least one groove of substantially uniform width therein adapted to assist the transportation of said grain from said feeding portion to said grinding portion, said groove beginning at a point adjacent but spaced from the central opening of the stone and spiraling toward the periphery of the stone, and power means for rotating the rotor stone relative to the stator stones.
 2. A grain grinder as defined in claim 1 wherein said stator stone comprises: a central opening through which grain is supplied to the feeding portion of the rotor stone, a first surface extending about the periphery of said opening and tapering outwardly from said opening at a relatively steep angle, a second surface extending about the periphery of said first surface and tapering outwardly from said first surface at a relatively moderate angle, and a third surface extending about the periphery of said second surface normal to the axis of said opening.
 3. In a grain grinder as defined in claim 2, wherein said rotor stone further comprises blower means comprising a plurality of turbine blades radially spaced around the periphery of the rotor stone to assist in transporting grain product after it has been ground.
 4. In a grain grinder having a housing, a stator stone and a rotor stone, the improvement comprising an axially displaceable mounting plate upon which the stator stone is mounted, the weight of the plate being carried by the housing and externally adjustable means comprising a single screw rotatably secured to the housing and threadedly engaging the stator stone mounting plate so as to axially displace the mounting plate and thereby vary the clearance between the stator stone and the rotor stone when the screw means is rotated.
 5. A grain grinder as defined in claim 4 wherein said screw means comprise a handle-pointer manually displaceable to rotate the screw means and an indicator plate having indicia thereon to visually indicate the clearance between said stones.
 6. In a grain grinder as defined in claim 5 wherein said indicating plate is adjustable relative to the stator stone to accommodate calibration between the separation of the rotor and stator stones and the indicia.
 7. In a grain grinder as defined in claim 4 wherein said adjustable means further comprises locking means to maintain a predetermined clearance between the stator and rotor stones.
 8. In a grain grinder as defined in claim 4 wherein said mounting plate comprises a chute portion adapted to feed grain from a grain source to the clearance between the rotor and stator stones.
 9. A grain grinder comprising a housing, a rotor stone mounted for rotation in a vertical plane, means for rotating the stone, a stator stone spaced from and in general alignment with the rotor stone, means coupled to the stator stone for delivering grain through an opening in the stator stone to a grinding location between the stator and rotor stones, and externally adjustable means for varying the space between the rotor and stator stones, said adjustable means comprising horizontally oriented screw means rotatable to axially displace the stator stone relative to the rotor stone, said rotor stone having at least one groove in the grinding face thereof to generally uniformly distribute grain to the periphery of the rotor stone for grinding, said stator stone having a tapered surface extending outwardly about the periphery of said opening and a second surface extending about the periphery of said tapered surface normal to the axis of said opening in facing relation with the grooved surface of said rotor stone. 